Certain dental or medical procedures cause unbearable discomfort to the patient and require some form of local anesthesia prior to commencement. The central nervous system is responsible for processing sensory information relayed by sensory neurons called receptor cells, neural pathways, and parts of the brain involved in sensory perception. Senses are transducers from the physical world to the mind, via the central nervous system, where we interpret the information, creating our perception of the world around us.
There are two basic types of anesthesia in use. The first is a general anesthesia which causes a full loss of consciousness thereby adding serious risk to the patient. The second is a temporarily induced and fully reversable local anesthesia which has significantly less risk to the patient facilitated by parenteral placement via hypodermic needle of a local anesthetic like Lidocaine® to suppress the pain sensing and signal transduction pathway to the brain via nerves near the procedure site alleviating the pain.
Local anesthetic solutions commonly have an acidic pH level of around 3.5 to extend their shelf life and enhance stability thus making them significantly different from the human body's normal pH level. A delay in the onset of anesthesia is caused by the time needed for the body to naturally neutralize the anesthetic preparation's low pH which is required to enable the anesthetic to pass through the walls of the sensory nerve cells.
By mixing the local anesthetic solution with a predetermined amount of a neutralizing solution like sodium bicarbonate having a pH of around 8.4 just prior administering it to the patient, the pH of the local anesthetic can be adjusted to be closer to the patient's body pH of 7.4 to facilitate a shorter onset time of anesthesia and more pronounced anesthetic effect which is beneficial to the patient. This also increases the efficiency of the dentist, or medical practitioner by reducing the time required to complete the painful procedure.
The process of modifying the pH of a final preparation is known to those skilled in the art as alkalization or buffering. If the preparation is buffered too far in advance of its use, it will precipitate and form solid crystals which could cause tissue damage or additional pain or discomfort if injected into a patient. Over time, the pH levels of preparations buffered too far in advance will also continue to rise.
Others have provided commercially available devices to buffer local anesthetic preparations. This includes the Onpharma® buffering pen. This system is complicated to use and subject to error as it has many steps that need to be performed in a specific sequence, each of which takes time. Due to the sheer number of injections administered each day by the dentist or medical practitioner, this device is cumbersome and impractical to use.
Another downfall of existing anesthetic buffering systems, especially Anutra® is that they take up precious counter space in the operatory as well as increasing inventory with costly disposables, special syringes, and handheld peripheral components requiring storage space in the dental office.
There is, therefore, a need for an improved device and process for buffering local anesthetics immediately prior to administration to the patient on demand.